A driver state monitoring (DSM) system detects whether an occupant in a driver seat of a vehicle is attentive or inattentive, such as drowsy. Some DSM systems receive input from an electric power steering system and analyze a steering pattern. Some DSM systems use lane-monitoring cameras to detect whether the vehicle is straying from a lane. Some DSM systems measure physiological data like heart rate or skin conductivity. Some DSM systems use a camera monitoring the occupant to, e.g., detect whether eyelids of the occupant are down too long or frequently.
Vehicles are typically equipped with sensors to detect whether seatbelts are buckled. These sensors are typically located in a buckle of a restraint system. For example, the vehicle may include reed switches inside each of the buckles to detect whether a clip of the seatbelt is buckled into the buckle.
But sensors located in the buckle cannot determine if the seatbelt is buckled, but buckled improperly. Furthermore, the sensors are an additional component and cost above the driver state monitoring system.